The present invention relates to an apparatus for recovering a volatile organic compound used in a process for increasing the filling capacity of tobacco. More particularly, the invention relates to an apparatus which will recover vapors used in a batch type process in which the batch of tobacco is impregnated with an organic compound then the tobacco is subjected to a stream of gas heated to a temperature above the boiling point of the organic compound impregnant whereby the impregnant is volatilized and the vapor given off is recovered and used again.
As is well known in the art, there are numerous processes for increasing the filling capacity of tobacco, and some of the known processes use a volatile organic compound to impregnate the tobacco and a hot gas to volatilize the organic compound and expand the tobacco. Previous embodiments of these processes are described in U.S. Pat. Nos. 3,524,451; 3,524,452; and 3,575,178. The latter two patents disclose processes which have a continuous in-feed and have been identified as "continuous processes."
Another of the presently known processes for increasing the filling capacity of tobacco is described in U.S. Pat. No. 3,753,440. This process is identified as a "batch process" because of its non-continuous nature. In the "batch process," a bed of tobacco is established in a hermetically sealed chamber which is vacuumized. The tobacco is contacted with the volatile organic compound which impregnates the tobacco and thereafter a drying gas is passed through the tobacco to remove a portion of water and the compound in the tobacco. Finally, a hot gas is passed through the bed of tobacco to volatilize the organic compound and, thus, expand the tobacco.
One of the aspects of utilizing a process such as the one described in the U.S. Pat. No. 3,753,440 is the recovery of the organic compound used to impregnate the tobacco. The present invention provides a unique recovery system in which a substantial amount of the organic compound can be recovered; furthermore, several items of equipment normally associated with a conventional recovery system are eliminated.